Compressor control means



p 1943- c. R. NEESON 2,329,931

COMPRES SOR CONTROL MEANS Filed Nov. 26, 1941 SSheets-Sheet 1 E N T R6B%drzes 75. N gro-41x N 022.4, Giza 8,- NW...

ATTORNEY5' Sept. 21, 1943. c. R. NEESON COMPRESSOR CONTROL MEANS FiledNov. 26, 1941 3 Sheets-Sheet 2 INVENTOR BY NM xii, 124 f ATTORNEYS.

Sept. 21, 1943.

C. R. NEESON COMPRESSOR CONTROL MEANS Filed Nov. 26, 1941 3 SheetsSheet3 All e a J z r h C Y B 1 k.

Patented Sept. 21, 1943 PATENT OFFICE COWKESSOR CONTROL MEANS -Cles R.Non, Dayton, Ohio, assignor to Chrysler Corporation, Detroit, Mich, acorporation of Delaware Application November 26, 1941, Serial No.420,559

2 Claims. (Cl. 230-24) My present invention relates to the control ofcompressing means for compressing a gaseous cally comprises animprovement upon the come pressor unloading means disclosed and claimein my Patent No. 2,185,473, issued January 2. 1940, but, as willpresently appear, the invention hasv application in a variety or formsof compressors. 1 f

One object of the invention is to provide means for preventing theloading oi acompressor until a predetermined time interval aftercommencement of cyclical operation of the compressing mechanism. Acompressing mechanism usually comprises a suction valve and a dischargvalve operating inconjunction with a piston, which parts go throughcycles of operation including the drawing of gas through the suctionvalve, compressing thereof by the piston and discharge of the compressedgas through the discharge valve. A compressor may comprise a singlepiston and set ofvalves or it may comprise a plurality of pistons eachwith its own set of valves.=

In the present disclosure the compressor comprises a. plurality ofreciprocating pistons, each with its own set of valves, located radiallyabout the compressor crankshaft. In accordance ,with

the present invention a single compressing means or a plurality ofcompressing means may be controlled to prevent the application of loadto the prime mover, i. e., to prevent the compression of the gaseousmedium, until a predetermined length of time after commencement ofcyclical operation of the compressing means.

The principal purpose of the present invention is to permit theapplication of an inexpensive type of motor, or other primev mover, tothe driving of gaseous medium compressors. By preventor fuel consumptionof the prime mover is matelially reduced. This is of special importancein some localities where the consumer charge for useor electric currentis based upon the starting inrush current peak. It the starting inrushis Just sufllcient to overcome the inertia of the rotor v and operatingparts of the compressing means,

the stand-by charge or peak load charge may be;

materially reduced.

A further object of the-present invention is to Q provide meansautomatically and instantaneously to render the compressing meansinoperative until a predetermined time interval after stoppage of theprime mover. This i of particular importance in certaininstallations-wherein a repeating starter may be employed, such as, forexample, in a compressor connected to an internal combustion engineprovided with an automatically repeating starter mechanism which isdesigned to operate a plurality of times in spaced succession providedthe internal combustion engine does not immediately start. Suchmechanisms fail to take into account the fact that the reason forinability to start the internal combustion engine might be the inabilityof the starting motor to carry the compression load as well as toovercome the inertia of the internal combustion engine and thecompressor. In the present invention, upon cessation of cyclicaloperation of the compressing means, the compressing means is immediatelyrendered ineffective to compress. the gaseous medium and remains in suchineffective state for a predetermined length of time which may be suchas to exceed the length of time required for the engine to reach fullspeed.

A further object of the present invention is to safeguard the rotor orother portions of electric motors employed to operate refrigerantcompressing means. It sometimes happens, such as occasionally caused bylightning striking the power lines, that the rotor is momentarily lockedagainst rotation due to a reversed current surge greater than the normalcurrent supply to the motor. If, after passage of the lightning surge,the rotor is expected immediately to pick up the full compression loadthe windings of the motor may be so overloaded as to cause theinsulation to burn and cause a short-circuit. A similar situation existswith regard to the human element in that an untrained operator or someunauthorized person may flick the starting switch on and off in rapidsuccession. In either event or in any other similar event, the presentinvention is designed to relieve the motor of the compression load untilthe motor has been given the opportunity to achieve full speed.

These and other objects and advantages of the present invention will bemore readily apparentto those skilled in the art upon inspection of theaccompanying drawings taken in connection with the followingspecification wherein like numerals refer to like parts throughout.

In the drawings,

Fig. '1 discloses a compressor embodying a pinrality oi compressingmeans. as disclosed in'my Patent No. 2,185,473, issued Janua y 2, 1940,the compressor being mounted in a condensing unit for a refrigeratingsystem and driven by an e1ec-'- tric motor;

Fig. 2 is a longitudinal, vertical section taken through the compressorof Fig. 1, certain parts of the sectional view being on irregular planesfor the purpose of complete disclosure;

Fig. 3 is a vertical section through a time delay relay comprising aportion of the present invention;

Fig. 4 is a vertical section through a valve comprising a portion of thepresent invention.

Fig. 5 is an axial section through one of the compressing cylinders andpistons; and

Fig. 6 is a horizontal section through the master valve and master valvecontrolling means of the compressor.

The usual condensing unit for a refrigerating system comprises acompressor i0 driven by a prime mover, in this case an electric motorII, and a condenser I2 into which the compressed refrigerant isdischarged by the compressor and from which the cooled refrigerant maybe withdrawn through a discharge line [3 having connection to thecooling portion of the refrigerating or air conditioning system (notshown) from which the expanded refrigerant is returned to the compressorthrough a suction pipe M.

It is to be appreciated that the compressor l0 may comprise an aircompressor drawing air from the atmosphere through an inlet l4 anddischarging the compressed air into a receiver mounted in the positionof the condenser i 2.

crankpin 24 of a crankshaft 25 connected to the prime mover ll. Cyclicaloperation of the compressing means would normally commenceinstantaneously with the operation of the prime mover to draw a gaseousmedium from the interior of the crankcase through the suction valve 2!,to compress the same and to discharge the compressed gaseous mediumthrough the discharge valve as fully explained in the aforesaid patent.

The compressor of the present invention is lubricated by a pump 30driven through gears 8i and 32, the latter of which is mounted on ashaft having driven connection to the crankshaft 25 through the mediumof a pin and slot connector 33. The pump, therefore, operatessimultaneously and coextensively with cyclical operation of thecompressing means. The pump, as fully explained in the aforesaid patent,draws lubricant from the crankcase and forces it through an outlet 34into a plurality of passages having communication with the bearings andmanifold through port I01.

control of a metallic bellows 31 influenced by the suction pressureexisting within the crankcaseof the compressor Ill. Lubricant may bepassed by the master valve 38 into one of several connections 38 eachleading to a space 39 containing a piston 40. The piston 40 is connectedby means of a piston rod ll to a yoke 42 surrounding the cylinder wall43 in which the piston 20 operates. The end of the yoke is provided witha roller adapted to climb a ramp 44 in order to raise a ring 45surrounding the cylinder 43 and which is provided with a plurality ofvertical rods 46. When fluid pressure is applied through the connection38 against the piston 40 the roller in yoke 42 is lowered down the ramp44 and the rods 46 are lowered to the position illustrated, in whichposition the suction valve 2| is seated so that the compressing means isloaded or will compress the gaseous medium. Upon release of fluidpressure from against the piston 40 a spring 4'! surrounding the pistonrod 41 forces the piston 40 outward and causes the roller in the end ofyoke 42 to climb the ramp 44, thereby raising the ring 45 and causingthe rods 48 to raise the suction'valve 2i from its seat. As long as thiscondition exists the compressing means is unloaded since gas drawn intothe cylinder through the suction valve would be forced back through thesuction valve into the crankcase without compression thereof.

Reference to Figs. 5 and 6 will more completely clarify the foregoing,the figures more completely disclosing details of the mechanism. Fig. 5shows that rods 46 are lowered by the combined thrust of springs Hill onthe rods 46 and springs llll on the suction valve 2|. Valve 2| may openwhen the pressure within cylinder 43 is lower than the pressure existingin suction manifold I02. thus permitting gas to enter the cylinderthrough ports I03. More gas may enter through ports I04 when the pistonis fully retracted. When the piston 20 is thrust outwardly the valve 2icloses and discharge valve I05 opens against the thrust of springsi06'held in discharge valve head 22, thus permitting escape ofcompressed gas into the discharge The suction manifold is connected tothe space surrounding bellows 31 (Fig. 6) through ports such as port H0(Fig. 5). Thus bellows 31 may contract or expand as the load on therefrigerating system, and hence the suction pressure, varies. Bellows 31may fully contract against the end of guidelimit tube iii, in whichposition all cylinders are loaded, or may fully expand, in whichposition all cylinders are unloaded. The bellows is connected to limitrod H2, which extends outward and is provided with an adjustment nut II3 which is adapted to strike the end of a tube H4 to limit the extentof movement of bellows 31 and hence limit the number of cylinders whichmay be unloaded. Tube H4 is slotted and the slot guides a regulatormember H5 which holds one end of a regulator spring H6, the other end ofwhich bears against the inner end of bellows 31. The position of memberH5 may be set by nut ill and locknut H8, threaded onto tube H4, toregulate the pressure of spring I I6 and hence determine the range ofpressures at which the bellows expands or contracts. Bellows 31 is alsoconnected to a rod I20 pivotally connected to a rocker arm I 2! mountedon the body of master valve 36 and pivotally connected to the mastervalve rod 50. The master valve rod 50 is thus caused to move in ratio tothe movements of the following operation thereof.

Complete details and a more detailed explanation of the individualcylinder unloading means may be found in the aforesaid patent, whichalso discloses more complete details and. explanation The selection ofthe pistons 40 which are to have fluid pressure applied thereto to causeunloading of the compressing means associated therewith is sub- Ject toa condition of the gaseous medium being compressed, such as the suctionpressure existing within the crankcase of the compressor. This isefiected by the metallic bellows 31 which may expand or contract tocause movement oi themaster valve rod 60 in the master valve 36.

' Movement-of the master valve rod 50 causes connection of one or moreof the connecting tubes 38 to the source of fluid pressure so 'as tocause loading of the individual compressing means to which the tubes 38lead, or disconnection there with resultant unloading. Some or all ofthe tubes 38 may be disconnected, or, vice versa,

some or all of the tubes 38 may be connected to the source of fluidpressure.

When the prime mover stops in a refrigerating system the pressure in thecrankcase increases. such increase soon causing complete collapse of thebellows 31 and complete connection of the unioading means to the sourceof fluid pressure. As soon as the prime mover starts cyclical operationof the compressing means again, simultaneous operation of the pump 30commences. For the first few rotations of the crankshaft 25 insufficientfluid pressure is created by the pump 30 to cause movement of thepistons 40 and resultant loading of any of the compressing means. In avery short period of time, such as one-fifth of a second when the primemover is operated by 60-cycle current at 1,750 R. P. M., suflicientfluid pressure will be generated by the pump to cause movement of all ofthe pistons 40 and loading of all of the compressing means. Thereafter,as the suction pressure of the refrigerat ing system is reduced, thebellows 31 expands to disconnect one or more of the tubes 38 and causeunloading of one or more of the compressing means so that the capacityof the compressor automatically varies in accordance wiht the load onthe refrigerating system; hence the motor consumes power variably inproportion to the load on the refrigerating system.

In most installations the short period of time required to build upsumcient fluid pressure, oneiifth of a second in the above examplerepresenting 12 cycles of alternating current, is suflicient for themotor to overcome its own inertia and the inertia of the compressingmeans and attain suflicient speed to carry the full compressing load.The present invention is designed to take care of the unusualinstallation or to make absolutely certain that the usual installationwill function, and to reduce. the starting torque in any installation.

. means comprises a time delay relay l and a by-pass valve I8 operatingto break the connection between the pump 30 and the master valve 33until it is absolutely certain that the prime mover is operating at fullspeed. The time delay relay 68 preferably comprises a solenoid 51, thewindings of which are connected by wires 58 to the power leads of theprime mover, in the example shown to two wires of a three-phase system.The core 80 of the solenoid is provided with a piston 61 operating in adash-pot 62, the piston 6| being provided with a metering orifice 63 anda check valve 84 so arranged as to open upwardly. Upon energization ofthe solenoid 51 the core 60 will be drawn upward, the rate of travel ofthe core being held to that permitted by the escape of fluid from abovethe piston 6! through the metering orifice 63. The core 60 hassuiflcient travel to operate an insulated plunger which closes contacts66 to complete a circuit including a second solenoid 61 which drawscurrent from the power leads to the prime mover and which operates theby-pass valve 56. The closing of contacts 86 is delayed a predeterminedintervalof time depending upon the rate of escape of the fluid in thedash-pot 62 after initial energization of the prime mover II. On theother hand, opening of the contacts 66 may be substantiallyinstantaneous due to the rapid escape of the fluid through the checkvalve 64 when the solenoid is deenergized. It is to be appreciated thatthe present disclosure is relative schematic, there being many suchdevices for accomplishing timed closing of the contacts 66 andsubstantially instantaneous opening of the contacts 66.

The by-pass valve 56 preferably comprises a core Ill attached to a valveplunger H provided with an opening "of considerable length. The body ,13of the valve is-provided with three passages", 15 and 16 in verticalalignment. The .valve 56 is attached to the crankcase cover I1,

and the openings l4, l5, and 16 are aligned with matching openings l8,l9, and 80, respectively, in the coverl'l. The opening 18 leads directlyinto the interior of the compressor 'so that fluid passing therethroughdrains back to the pump 30. The opening 19 is connected to a tube 8|which comprises the supply tube to the master valve 36, and the opening80 is connected to a tube 82 which communicates with the passage 35leading to the discharge side of the pump 30.

When the solenoid 61 is deenergized due to opening of the contacts 66,the valve plunger H is in the position shown in Fig. 4 so that theoutput of the pump is blocked from the master valve 36. As soon as thedash-pot device has closed the contacts 66, the solenoid 6'! isenergized to raise the plunger H in order to connect tube 8| to tube 82,thus causing the immediate application of fluid pressure to the mastervalve 36.

The present invention comprises the addition to the foregoing system ofa time delay mechanism to prevent connection of the fluid pressurecreating means to the fluid pressure operated loading means, until apredetermined safe length of time after commencement of cyclicaloperation of the compressing means. The time delay Upon such applicationof fluid pressure all of the pistons 40 will be operated against thesprings 41 to load all of the compressing means since the master valvewill have been moved to entire connecting position by collapse of themetallic bellows 31. The arrangement of the plunger H is such thatimmediate discontinuance of power to the prime mover or reversal ofcurrent thereto would result in immediateunloading of all of thecompressing means since the plunger H would immediately drop, thusconnecting the master valve to the interior of the crankcase through theopening 18 and permitting the lubrican't therein to flow out and permitthe springs 41 to operate-the unloading means. Reapplication of currentin the next moment would not cause reloading oi the compressor untilafter the dash-pot device had been overcome.

As fully explained in the aforesaid patent the operation of the mastervalve 38 may be accomplished by some other condition oi the gaseousmedium being compressed, such as the pressure in the receiver into whichthe compressed gas is discharged. It should be apparent to those skilledin the art that such a modification would permit the application of thepresent invention to an air compressing mechanism.

It should be obvious to those skilled in the art that the presentinvention may be applied to the combination of a compressor and aninternal combustion engine of the type having automatic starting means,such as by causing the energization of the solenoid 61 to occursimultaneously with application of current to the internal combustionengine starting motor.

It should be apparent to those skilled in the art that many othermodifications in the invention and application of the present invention,as well as in the details thereof may be realized from the teachings ofthe present disclosure. All such modifications as come within the scopeof the following claims are considered a part or my invention I claim:

1. A compressor comprising a prime mover, a cyclically operatingcompressing means driven by said prime mover and adapted normally tocompress a gaseous medium at each cycle of operation; means to vary thecompressing capacity of said compressing means from no capacity to fullcapacity automatically in response to a condition 01 the gaseous mediumincluding fluid pressure creating means eflective simultaneously withcyclical operation of said compressing means, fluid pressure operatedmeans for eflecting the loading of said compressing means to fullcapacity when connected to said fluid pressure creating means, andspring means for effecting the unloading of the compressing means to nocapacity when said fluid pressure operated means is disconnected fromsaid fluidpressure creating means; and a time delay mechanism preventingthe application of fluid pressure created by said fluid pressurecreating means to said fluid pressure operated means until apredetermined length of time after commencement of cyclical operation ofsaid compressing means to delay the loading of said compressing meansfor sufficient time to permit said prime mover to attain operatingspeed.

2. A compressor comprising a prime mover, a cyclically operatingcompressing means driven by said prime mover and adapted normally tocompress a gaseous medium at each cycle of operation; means to vary thecompressing capacity of said compressing means from no capacity to fullcapacity automatically in response to a condition of the gaseous mediumincluding fluid pressure creating means effective simultaneously withcyclical operation of said compressing means, fluid pressure operatedmeans for effecting the loading of said compressing means to fullcapacity when connected to said fluid pressure creating means, springmeans for effecting the unloading of the compressing means to nocapacity when said fluid pressure operated means is disconnected fromsaid fluid pressure creating means, and a master valve between saidfluid pressure creating means and said fluid pressure operated meansresponsive to a condition of the gaseous medium for connecting ordisconnecting said fluid pressure creating means and said fluidpressureoperated means; and a time delay mechanism preventin the passageoi! fluid under pressure from said fluid pressure creating means throughsaid master valve until a predetermined length of time aftercommencement of cyclical operation or said compressing means even thoughsaid master valve may be open to delay the loading of said compressingmeans for suflicient time to permit said prime mover to attain operatingspeed.

3. A compressor comprising cyclically operating compressing meansadapted normally'to compress a gaseous medium at each cycle ofoperation; means to vary the compressing capacity or said compressingmeans from no capacity to full capacity automatically in response to acondition of the gaseous medium including fluid'pressure creating meanseflective simultaneously with cyclical operation of said compressingmeans, fluid pressure operated means for eil'ecting the loading of saidcompressing means to full capacity when connected to said fluid pressurecreating means, spring means for effecting the unloading of thecompressing means to no capacity when said fluid pressure operated meansis disconnected from said fluid pressure creating means, and a mastervalve between said fluid pressure creating means and said fluid pressureoperated means responsive to a condition oi! the gaseous medium forconnecting or disconnecting said fluid pressure creating means and saidfluid pressure operated means; and a time delay mechanism preventing thepassage of fluid under pressure through said master valve until apredetermined length of time after commencement of cyclical operation01' said compressing means even through said master valve may be open,said time delay mechanism including a solenoid adapted to be energizedupon commencement of cyclical operation of said compressing means, aswitch adapted to be closed by said solenoid when energized, and adash-pot delay mechanism causing slow action of said solenoid.

4. A compressor comprising cyclically operating compressing meansadapted normally to compress a gaseous medium at each cycle ofoperation; means to vary the compressing capacity or said compressingmeans from no capacity to full .capacity automatically in response to acondition of the gaseous medium including fluid pressure creating meanseffective simultaneously with cyclical operation of said compressingmeans, fluid pressure operated means for eflecting the loading of saidcompressing means to full capacity when connected to said fluid pressurecreating means, spring means for effecting the unloading of thecompressing means to no capacity when said fluid pressure operated meansis disconnected from said fluid pressure creating means, and a mastervalve between said fluid pressure creating means and said fluid pressureoperated means responsive to a condition of the gaseous medium forconnecting or disconnecting said fluid pressure creating means and saidfluid pressure operated means; and a time delay mechanism preventing thepassage of fluid under pressure through said master valve until apredetermined length of time after commencement of cyclical operation ofsaid compressing means even though said master valve may be open, saidtime delay mechanism including a solenoid adapted to be energized uponcommencement of cyclical operation of said compressing means, a switchadapted to be closed by said solenoid when energized, a

. v dash-pot delay mechanism causing slow action of said solenoid, and asolenoid'opera'ted valve between said fluid pressure creating means andsaid master valve adapted to be energized upon closing 01! said switchto complete the fluid connection or said fluid pressure creating meansand said fluid pressure operated means.

pressure to said loading means for a predetermined length or timeafter-commencement of operation of said fluidpressure' creating meansincluding a valve between said fluid pressurecreating means and saidloading means and electrical means for opening said valve to permit theapplication of fluid pressure to said loading means, said electricalmeans comprising a first solenoid for opening said valve when energized,

a switch in series with said first solenoid for permitting current toflow through said first solenoid when closed, and a second solenoid forclosing said switch. 7

6. A compressor comprising loading means dependent upon fluid pressurefor activating power, fluid pressure creating means operatedsimultaneously with cyclic operation of the compressor for creating suchfluid pressure, and time delay means for preventing the application offluid pressure to said loading means for a predetermined length of timeafter commencement of operation of said fluid pressure creating meansincluding a valve between said fluid pressure creating means and saidloading means and electrical means for opening said valve to permit theapplication of fluid pressure to said loading means, said electricalmeans comprising a first solenoid for opening said valve when energized,a switch in series with said first solenoid for permitting current toflow through said first solenoid when closed and a second solenoid forclosing said switch, said second solenoid being included in a circuitadapted to be energized fluid pressure creating means operated simulta-.neously with cyclic operation or the compressor for creating such fluidpressura'and time delay means for preventing the application of fluidpressure to said loading means fora predetermined length of time aftercommencement of operation of said fluid pressure creating meansincluding a valve between said fluid pressure ore-- ating means and saidloading means and electrical means for opening said valve to permit theapplication or fluid pressure to said loading means, saidelectrical-means comprising a first solenoid for opening said valve whenenergized, a switch in series with said first solenoid for permittingcurrent to flow through said first solenoid when closed, a secondsolenoid for closing said switch, said second solenoid being included ina circuit adapted .to be energized simultaneously with commencement ofcyclical operation of said compressor, and means for delaying theeflectiveness of said second solenoid to close said switch for apredetermined interval of time after becoming energized including ,a.dash-pot device.

9. A compressor comprising loading means dependent upon fluid pressurefor activating power, fluid pressure creating means operatedsimultaneously with cyclic operation or the compressor for creating suchfluid pressure, and time delay means for preventing the application orfluid pressure to said loading means for apredetermined length of timeafter commencement of operation of said fluid pressure creating meansincluding a valve between said fluid pressure creating means and saidloading means and electrical means for opening said valve to permit theapplication of fluid pressure to said loading means, said electricalmeans comprising a first solenoid for opening said valve when energized,a switch in series with said first solenoid for permitting current toflow through said first solenoid when closed, a secondesolenoid forclosing said switch, said second solenoid being included in a circuitadapted to be energized. simultaneously with commencement of cyclicaloperation of said compressor, and means for delaying the efiectivenessof said second solenoid to close simultaneously with commencement ofcyclical operation of said compressor.

7. A compressor comprising loading means dependent upon fluid pressurefor activating power, fluid pressure creating means operatedsimultaneously with cyclic operation of the compressor for creating suchfluid pressure, and time delay means for preventing the application offluid pressure to said loading means for a predetermined length of timeafter conmiencement of operation of said fluid pressure creating meansincluding a valve between said fluid pressure creating means and saidloading means and electrical means for opening said valve to permit theapplication of fluid pressure to said loading means, said electricalmeans comprising a first solenoid for opening said valve when energized,a switch in series with said first solenoid for permitting current toflow through said first solenoid when. closed, a second solenoid forclosing said switch, said second solenoid being included said swltchiora predetermined interval of time after becoming energized 8. Acompressor comprising loading means dependent upon fluid pressure foractivating power,

said switch for a predetermined interval of time after becomingenergized including a dash-pot device; and means for substantiallyinstantaneously unloading said compressor by removal of fluid pressurefrom said loading means upon cessation of cyclical operation of thecompressor.

10. A compressor comprising loading means dependent upon fluid pressurefor activating power, fluid pressure creating means operatedsimultaneously with cyclic operation-of the compressor for creating suchfluid pressure, and time delay means for preventing the application offluid pressure to said loading means for a predetermined length of timeafter commencement of operation of said fluid pressure creating meansincluding a valve between said fluid pressure creating means and saidloading means and electrical means for opening said valve to permit theapplication of fluid pressure to said loading means, said electricalmeans comprising a first solenoid for opening said valve when energized,a switch, in series with said first solenoid for permitting current toflow through said first solenoid when closed, a second solenoid forclosing said switch, said second solenoid being included in a circuitadapted to be energized simultaneously with commencement of cyclicaloperation of saidcompressor, and means for delaying the effectiveness ofsaid second solenoid to close said switch for a predetermined intervalof time after becoming energized including a dash-pot device; and meansfor substantially instantaneously unloading said compressor by removalof fluid pres-- sure from said loading means upon cessation of cyclicaloperation or the compressor including a connection between said loadingmeans and the

